67131809 has 2 divisors, whose sum is σ = 67131810. Its totient is φ = 67131808.

The previous prime is 67131803. The next prime is 67131851. The reversal of 67131809 is 90813176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53699584 + 13432225 = 7328^2 + 3665^2 .

It is a cyclic number.

It is not a de Polignac number, because 67131809 - 2⁸ = 67131553 is a prime.

It is a super-2 number, since 2×67131809² = 9013359559224962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (67131803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33565904 + 33565905.

It is an arithmetic number, because the mean of its divisors is an integer number (33565905).

Almost surely, 2^67131809 is an apocalyptic number.

It is an amenable number.

67131809 is a deficient number, since it is larger than the sum of its proper divisors (1).

67131809 is an equidigital number, since it uses as much as digits as its factorization.

67131809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 67131809 is about 8193.4003319745. The cubic root of 67131809 is about 406.4209781606.

The spelling of 67131809 in words is "sixty-seven million, one hundred thirty-one thousand, eight hundred nine".